OBJECTIVE To investigate the matrilineal patterns in birth weight across generations and to assess the role of female offspring in perpetuating these traits. RESULTS Across generations, the matrilineal trend for high and low birth weight was much more pronounced for female than male offspring. With the delivery of ample nutrition and better health care in laboratory over feral conditions, there was a dramatic increase in the birth weight of daughters within certain matrilines; this, in turn, had a beneficial influence on the pregnancy outcomes of the female descendants in those lineages. By contrast, females born to low birth weight matrilines were at greater risk for poor reproductive outcomes in adulthood DISCUSSION Utilizing a multigenerational data set that provided 40 years of information on the pregnancies and pedigrees of 1600 infants, we conducted a series of analyses to evaluate the relationship between familial and contemporaneous pregnancy factors and infant birth weight. We first established a normative model for predicting the birth weights of average-for-date (AFD) infants and then examined the birth weight transmission patterns for monkeys descended from small-for-date (SFD) and large-for-date (LFD) birth weight matrilines. Both brothers and sisters of LFD infants exhibited enhanced fetal growth, but for SFD probands, only the sisters experienced significant intrauterine growth constraint. In addition, females born SFD were at greater risk for poor reproductive outcomes in adulthood, and they perpetuated the matrilineal pattern of low birth weight by selectively influencing the prenatal growth of their daughters, but not their sons. Collectively, these findings provide evi dence that an intrauterine mechanism transmitted through female progeny can regulate fetal development and may be partially responsible for the intergenerational persistence of certain pregnancy outcomes within certain families. FUTURE DIRECTIONS We plan to investigate the effect of intrauterine growth on later endocrine and metabolic functioning. Further, we hope to determine whether the resultant alterations in the developmental trajectories of these systems influence the timing of sexual maturation and the reproductive health of female monkeys. FUNDING NIMH MH11579-02; MH41959-13